HELP! My laser is printing patterns out of square!

[gellfex]

Part of my workflow is often printing patterns on paper to glue down to 6061 plate for cutting and drilling. Today I noticed I couldn't line up a printed square to the shear cut edges of the plate. WTF? I checked the plate with a square, assuming it was the problem and it was fine, checked my drawing too. Turns out the printed pattern was true along the length of the 11x14 sheet, but the perpendicular was out by ~0.060" over 7". The printed lined were simply not perpendicular. So I made it into a PDF and sent it to the HP laser in the family room and it printed just fine.

How the hell can this happen!! DO I need a new printer? This is a HP 1018 that has been utterly dependable.

[tyrone shewlaces]

You need to tram your head.




but seriously. I'm not sure what is happening, but it could be the feed is no longer square to the print head. Total guess, but that's the only thing my mechanical brain can think of.

[gellfex]

but seriously. I'm not sure what is happening, but it could be the feed is no longer square to the print head. Total guess, but that's the only thing my mechanical brain can think of.

That would be quite a trick, wouldn't it? These things aren't built with slop.

[_Paul_]

Might be a paper "pickup" problem perhaps skewing the paper slightly as it takes it from the tray, IMHO would try cleaning the pickup/feed rollers.

Is the paper to dimension?

Paul

[elf]

What kind of material is square? Is it metal or plastic?

[dave_r]

Is it that you printed a vertical and a horizontal line on the paper, and they aren't perpendicular?

Or that the lines aren't parallel/perpendicular to the edge of the piece of paper?

[Paul Alciatore]

This sounds like a mechanical problem in the printer. Perhaps something is loose inside the printer. If the long edge (14" you said) lines up and the lines perpendicular to that are now perpendicular, then it is possible/probable that the rails that the print head rides on are a bit out of line.

Or the roller is off. Look for something loose.

[J Tiers]

That comes up as a laser. The short dimension lines should be across the paper movement. So something is presumably shifting as the paper moves through.

Is the entire pattern skewed but all connected? I assume this is the case

Is the pattern skewed with lines that should connect but do not? You would have noticed this

[Highpower]

I had a similar issue once with my old HP Laserjet 4L that began printing skewed horizontal lines after I took it apart and gave it a good cleaning. (Dust, spilled toner, etc. inside.) Apparently I had bumped mirror bar that sits on top of the laser/scanner head and moved it. It reflects the laser beam down through the top of the toner cartridge onto the photo drum. Loosening the screws at the ends of the bar allows it to pivot slightly to realign the beam parallel to the drum. It runs across the full width of the paper path. Luckily I found that in the troubleshooting section in the manual.

But it looks like your printer uses a 4 sided (square) rotating mirror on a motor instead of a straight flat bar like mine. I've no idea how to adjust one of those, or if it is even possible. If it's not a paper feed / tracking issue, that is the only other thing that I can think of.

[fjk]

paper slippage in the path maybe. look for lint/goop/etc on the feed rollers.

did something whack the printer, knocking all its delicate insides out of alignment?

did you try printing the pdf that you created onto the 1018? did you try other patterns (especially ones that have printed OK in the past)?

when you measured how square the bad image was, did you measure the one that you glued down or another, newly printed, one? could the glue have warped/twisted/distorted/f'ed the paper up?

just some random thoughts before all the morning coffee kicks in

frank

[pinstripe]

It does sound like slippage. Try to print a fine-ish grid. Might help you to see where it's going wrong. Print it a few times to see if the problem happens at the same point on each page.